CGRG Bibliography of Canadian Geomorphology
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Author : Bentley, S.; Hülse, P.; Church, I.; and Brucker, S.
Date : 2007.
Title : A remarkable sediment depocenter and environmental archive off the Great Whale River, Hudson Bay, Quebec.
Publication : ArcticNet 2007 Annual Scientific Meeting. December 11-14, 2007. Collingwood, Ontario.
Issue : Programme.
Page(s) : 32.
Abstract
As part of a study of fluvial sediment and freshwater flux into Hudson Bay, a sonar and box-core survey offshore of the Great Whale River (Quebec) was conducted during Leg 1 of the CCGS Amundsen 2007-2008 expedition. Fresh water discharge from the Great Whale River is presently approximately 20 cubic km/y from a drainage basin of 43,200 square km in northwestern Quebec, making it one of the larger rivers flowing into Hudson Bay. Present sediment discharge is not known, but is likely to be proportional to water discharge, and has been estimated at approximately 1,000,000 t/y from statistical hydrologic models (Bentley, 2006), and may be declining due to declining discharge and changing climate in the basin (Dery et al., 2005; Bentley, 2006). As a first step in constraining patterns of discharge that extend back beyond the ~40y instrument record, cores, multibeam, and subbottom sonar data were collected offshore of the river mouth, from a coastal basin of approximately 140 square km in extent. Boxcores were subsampled for X-radiography, granulometry, and sediment radiochemistry. Core samples are presently being analyzed for the particle-bound radioisotopes Be-7 (half-life=53.3d), Th-234 (half-life=24.1d) and Pb-210 (half-life=22.3yr), to elucidate spatial and temporal patterns in sediment flux and thus freshwater input on seasonal to centennial timescales. Preliminary results show that this offshore basin contains extensive deposits of terrigenous sediments that locally exceed 50m thickness, suggesting that this basin is constitutes a remarkable archive of environmental history in the form of stratified sediment deposits from the Great Whale River catchment. More detailed understanding will be derived from ongoing analysis of core and sonar data in hand, and proposed sampling in future years.
Bibliography of Canadian Geomorphology